There are a variety of exercise devices for the hand, forearm and wrist. Some employ a stationary torque or torsional member for resistance to turning or twisting. Generally the user's hands will grip each end of the exerciser, turning the ends in opposite directions with a force great enough to overcome the rigidity of the torsional member, such as Griffin U.S. Pat. No. 3,708,164 and Nielsen U.S. Pat. No. 3,084,547. Others employ hydraulic fluid as a resistance to twisting. A Rotary resistant torque is developed by restricting the flow of hydraulic fluid from one chamber to another between the hand grips of the exerciser, such as Stoecker U.S. Pat. No. 4,171,802. And others use friction disc as a resistance means. In this invention a pair of grips are rotated relative to each other with enough force to overcome the frictional engagement of disc-like members located between the hand grips, such as Struble U.S. Pat. No. 3,184,234.
Still these disclosures provide only an exercise of turning and rotating the grips about a fixed axis in a single plane. The Mitchell U.S. Pat. No. 3,428,311 disclosed a therapeutic exercising device for rehabilitation of the musculature of the upper extremity. The Mitchell disclosure comprises a base with a concave seat, a solid ball nested in this seat with a cage threaded onto the top of the base and over the solid ball, an upstanding bar mounted on the ball and a hand grip on the opposite end adapted to be grasped for twisting the bar and the attached ball 360.degree. in the cage. To increase resistance the cage can be screwed down onto the base and thus applying pressure to the solid ball and increasing frictional drag. The handle and bar are movable in arcs limited only by the diameter of the opening in the center of the annular seat. Such arcs may be varied 360.degree. relative to the polar axis of the ball. Therefore, it provides more versatility then the standard hand exerciser which only provides rotational resistance. But, the Mitchell invention provides exercise for only one hand at a time. In addition it is not compact and portable, it must be mounted to a bench or wall or clamped to a door opening.
The present invention is directed to a portable hand and wrist exercise unit which can be readily carried in a traveling case. It is especially designed for athletes, such as golfers, who desire to strengthen their hands and wrists, and is useful for persons suffering from arthritis who must continually strive for mobility or in the hand and wrist points. For every muscle in the appendages there is an equal and opposing muscle. This invention provides frictional resistance to both sets of muscles. The unit is especially designed for infinite angle dispositions which allows versatile use adaptable to any particular motion desired. In addition, it facilitates isometric exercise of the arms while hand exercise is progressing.